JPH0797704B2 - Method for manufacturing multilayer printed wiring board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a multilayer printed wiring board, and in particular, for the purpose of high-density mounting, a part of a conductor layer of a via hole is divided to form a plurality of via holes. The present invention relates to a method for manufacturing a multilayer printed wiring board having the same grid.

[Conventional technology]

High density integration of multilayer printed wiring boards (hereinafter referred to as “multilayer boards”) is progressing in order to achieve high integration of LSIs and ICs, high performance of electronic devices and improvement of economic efficiency.

Two main measures are taken to increase the density of multilayer boards. The first is the increase in the number of conductor layers, that is, the increase in the number of layers, and the second is the increase in the number of wirings between the basic lattices. However, in the first measure, the number of via holes connecting the conductor layers between layers is increased, and in the second measure, the increase in the number of wiring is
Wiring capacity is severely limited. Therefore, the reduction of the via hole diameter and the thinning of the wiring conductor have been dealt with, but these all hinder the manufacturability of the multilayer board.

As a method for solving this problem, a multilayer board having a viad via hole and a surface (blind) via hole has been devised.

Hereinafter, a typical manufacturing method will be described with reference to FIGS. 3A to 3E as an example.

As shown in FIG. 3 (A), first, the laminated plate is subjected to drilling and panel plating, and then the surface via hole 13
A via hole is formed as much as possible, and then an inner layer circuit pattern 14a is formed only on one surface by a photo printing method to produce a surface via inner layer plate 15.

Similarly, as shown in FIG. 3 (B), drilling and panel plating are performed on the laminated plate to form via holes as much as the verid via holes 16, and then the inner layer circuit pattern is formed on both sides by photo printing. Forming 14b and 14c,
The Velidvia inner layer board 17 is produced.

Next, as shown in FIG. 3 (C), the two inner layer plates 15 described above are used.
The a, 15b and 17 are set by inserting the prepregs 6a and 6b.

Next, as shown in FIG. 3 (D), a multilayer molded substrate 10 in which the respective inner layer plates 15a, 15b, 17 are integrated by the prepreg layers 9a, 9b is obtained through the heating and pressing steps.

Next, as shown in FIG. 3 (E), through holes are drilled in predetermined positions of the multilayer molded substrate 10 to form the panel plating layers 18a, 18b, 18c.
Then, the through via hole 11 is formed, and photo-printing processing is performed to obtain the multilayer board 12 having the surface via holes 13a and 13b and the buried via hole 16 by the conventional manufacturing method.

In addition, a normal copper clad multilayer board is formed in the surface via hole, and a semi-through hole is drilled from the outer surface by N / C drilling, laser processing, etc., and then normal panel plating,
There is also known a manufacturing method (not shown) in which a surface via hole is obtained by performing a photo printing process and connecting an outer layer and an inner layer immediately below the outer layer with a semi-through hole.

[Problems to be Solved by the Invention]

The above-described conventional method for manufacturing a multilayer board has the following drawbacks.

First, the resin filled in the surface via hole and the buried via hole depends only on the resin contained in the prepreg. Therefore, the thickness of the inner layer plate is only about the same as that of the prepreg layer, and the thickness of this type of inner layer plate is about 0.3 to 0.4 mm at the maximum, and it is almost impossible to form a multilayer.

Therefore, when constructing via holes on the same lattice with multilayer plates that normally exceed 10 layer plates, surface via holes and verid via holes or through through holes are formed on the inner layer plate with double-sided structure. However, there are roughly two types of methods of using it as a via hole. In particular, in the latter through via hole, only one hole can be arranged on one grid point, and the higher the number of layers, the more disadvantageous the wiring accommodation becomes. Was causing a via hole neck problem.

An object of the present invention is to provide a method for manufacturing a multilayer board which has good wiring accommodability and enables high-density wiring.

[Means for Solving the Problems]

The method for producing a multilayer printed wiring board according to the present invention is a through-hole process for a laminated board having a double-sided or multi-layered structure, an outer layer circuit is formed, and a paste-like heat resistant resin is applied to the entire front and back surfaces of the laminated board. At the same time, a step of forming an intermediate laminated body by filling the inside of the through hole and then thermosetting it, and a step of inserting at least two sets of the intermediate laminated body by heat and pressure molding. It is molded in multiple layers including.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

1 (A) to 1 (E) are vertical cross-sectional views showing the manufacturing process of the first embodiment of the present invention in the order of steps.

In the first embodiment, as shown in FIG. 1 (A), an arbitrary portion of a laminated plate 2 (trial-produced as a 4-layer plate this time) which is previously laminated and has arbitrary inner layer conductors 1a and 1b is used. Through-hole processing is performed to form the divided via holes 3 as much as possible divided via holes in the future.

Next, as shown in FIG. 1 (B), a paste-type heat-resistant resin 4a in which bisphenol type epoxy resin is mixed with aluminum hydroxide in an amount of 20 to 50% is filled in the divided via holes 3 by a roll coater, and at the same time, At the same time, the heat-resistant resin 4a is also applied to the front and back of the laminated plate 2. After that, the temperature is 150 ℃,
90 minutes baking process, heat curing, intermediate laminate
Form 5a.

Next, as shown in FIG. 1 (C), two sets of intermediate laminated plates 5
a, 5b are prepared, prepregs 6a, 6b are inserted, and copper foils 7a, 7b having a thickness of 18 μm are arranged on the outermost layer. The pattern 8 was arranged on the surface of one of the intermediate laminated plates 5b.

Next, as shown in FIG. 1 (D), a multilayer molded substrate 10 in which the intermediate laminated plates 5a, 5b are integrated by the prepreg layers 9a, 9b, 9c is obtained through a heating and pressure molding process.

Next, as shown in FIG. 1 (E), the above-mentioned multilayer molded substrate 10
By applying through-hole processing and photo-printing processing according to the conventional method to the predetermined portions that can be electrically connected to the pattern 8 to form the through via holes 11, the multilayer board 12 according to the first embodiment is obtained.

2 (A) to 2 (D) are longitudinal sectional views showing the manufacturing method of the second embodiment of the present invention in the order of steps.

In the second embodiment, first, as shown in FIG. 2A, the intermediate laminated plate 5a is formed by the same manufacturing method as that of the first embodiment.

Next, as shown in FIG. 2 (B), as in the first embodiment, two sets of the intermediate laminated plates 5a, 5b are inserted through the prepregs 6a, 6b, 6c to form the copper foils 7a, 7b. Is placed on the outermost layer.

Next, as shown in FIG. 2 (C), a multilayer molded substrate 10 integrated with prepreg layers 9a, 9b, 9c through a heating and pressure molding process.
To get

Next, as shown in FIG. 1 (D), the through via hole 11 is formed by the same method as that of the first embodiment, and at the same time, the patterns 8a and 8b can be electrically connected from the outermost layer side. A semi-through hole is formed to the depth with an N / C driller, panel plating and photo printing are applied, and a surface via hole is formed.
13a and 13b are formed to obtain the multilayer plate 12.

In this embodiment, a wiring channel between the divided via hole and the outer layer pattern can be efficiently provided by combining with the conventional method of processing the surface via hole.
Moreover, since a large number can be obtained, there is an advantage that a higher density can be achieved.

〔The invention's effect〕

As described above, the present invention has the effects listed below by dividing the through-holes on the same lattice.

(1) When the through-holes are used as via holes, they can be arranged as divided via holes on the same lattice point, the wiring accommodability is improved, and high-density wiring is possible.

(2) It is possible to mold multiple high-thickness multi-layer boards with a large thickness, and especially when a large number of surface mount components are mounted on both sides, the wiring on the same layer surface should be connected to the surface via hole. It is possible to dramatically improve the wiring accommodating property by providing the via hole wiring divided by the combination and providing the wiring between the front and back sides by the through-hole type via hole.

[Brief description of drawings]

1 (A) to 1 (E) are longitudinal sectional views showing the manufacturing method of the first embodiment of the present invention in the order of steps, and FIGS. 2 (A) to 2 (E).
(D) is a longitudinal sectional view showing the manufacturing method of the second embodiment of the present invention in the order of steps, and FIGS. 3 (A) to (E) are shown in the order of steps explaining an example of the conventional manufacturing method. FIG. 1a, 1b, 1c, 1d …… Inner layer conductor, 2 …… Laminated plate, 3a, 3b …… Divided via holes, 4a, 4b …… Heat resistant resin, 5a, 5b …… Intermediate laminated plate, 6a, 6b, 6c …… Prepreg, 7a, 7b …… Copper foil, 8a,
8b ... Pattern, 9a, 9b, 9c ... Prepreg layer, 10 ... Multilayer molded substrate, 11 ... Through via hole, 12 ... Multilayer board,
13a, 13b …… Surface via hole, 14a, 14b, 14c, 14d
...... Inner layer circuit pattern, 15a, 15b …… Surface via inner layer board, 16 …… Velid via hole, 17 …… Velid via inner layer board, 18a, 18b, 18c …… Panel plating layer.

Claims (1)

[Claims] 1. A laminated plate having a double-sided or multi-layered structure is subjected to through-hole processing and outer layer circuit formation, and then a paste-like heat-resistant resin is applied to the entire front and back surfaces of the laminated plate, and both are combined.
A multilayer structure including a step of filling the inside of the through hole and then thermosetting to form an intermediate laminated body, and a step of inserting at least two sets of the intermediate laminated body through a prepreg and heating and pressurizing the intermediate laminated body. A method for manufacturing a multilayer printed wiring board, which comprises molding.